About make an audio power amplifier.

[audioguru]

I wasn't talking about getting stoned on drugs. I dreamed of flying because "I was better" than all the other people who could not fly because I had plenty of confidence.

 

[spec]

I had pretty good eyesight until I became about 40 years old then "my arms became too short to read" so I got closeup reading glasses. Then I could not see distant things or very close things so I got tri-focal lenses in my glasses. Then my eyesight faded into a blur because I became blind with cataracts. So I got my eyes fixed (synthetic lenses inside my eyes) and now they are fine and use glasses only for very close ups.

I have always loved music since I was little and I also have a good sense of rhythm. I could hear many frequencies and as a teenager I heard "ultrasonic" burglar detectors that were never turned off because they "could not be heard".
I can carry a tune or tune an instrument. I played a trombone (no frets) in my high school band I can sing and whistle tunes but not very well but the frequencies were/are always correct.

My hearing very gradually faded the high frequencies and is now normal for my age of 70, about -40dB to -50dB at 8kHz. I ran out of excuses that people mumbled and the TV produced muffled sounds. I went for a free hearing test and free demo hearing aids and they make my hearing like when I was young. It took a few weeks to get used to hearing normally again and I am glad the audiologist turned them up only a little every couple of weeks. Now after using them for hundreds of days and taking them off each night I feel like I am deaf for a few minutes, then putting them on each morning they sound too shrill for a minute or two.

Very interesting AG, and well put. How someone can play the trombone is beyond me.

I have always had plenty of confidence with everything I did/do. Maybe that is why I frequently dream that I can fly above other people by using a trick that is something like holding my breath (helium?) and see that they do not fly.

It took me a bit of time to decode the last part of what you said. My feeling is that you are not one person but probably three, going by your posts on ETO that is. The two people that I like are the clever and knowledgeable designer and the teller of stories of experiences, as in the above post. I hope you don't mind me saying this.

 

[Mikebits]

Very interesting AG, and well put. How someone can play the trombone is beyond me.

I played the trombone in the 7th grade (Just for 1 yr did not like band class), and I was too short to play the last note or 7th position, I think it was the C note. Also had trouble using the spit valve

 

[spec]

Yes I made assumptions, you clearly have a passion for Audio and this is normally the domain of people like AG. Its rare to have the interest you do and have normal/subnormal hearing, I have no doubt a good system would be more enjoyable to listen to, I just dont have the interest in sound apart from sound and light mixed, I am classed as cerebral visual and wish I could draw. I would love to play the guitar, but only if I can use relays etc to do it .

Hi again LG,
I am going to argue again- I don't especially have a passion for audio, but, pretty much like everybody on ETO, I am unexplainably fascinated by technology and engineering- it seems to be in the genes both from my mother's and father's side, where there was engineers in both lines. It just so happens that audio and electronics are intertwined. I spent years designing and making car ignition systems too but you would not say that I was passionate about ignition.

About HiFi: my view is totally negative and I think that even the very best, most expensive, reproducing systems simply cannot hold a candle to the real thing, not necessarily only music, but perhaps the sound of a drag racer revving up before the off, or the sound of Niagra falls. To me the average reproducing system whether, it be an Ipod, TV or radio is simply awful and what makes it worse, is that the poor performance is an unforced error. That is it could be fixed at no cost.

Just to illustrate the point, one of the engineers in our lab did a make-over of a cheap cassette recorder of the type that were common in the 1970s and 1980s. Originally it sounded so bad that it was often hard to recognize the tune being played and voice was unintelligible. Being interested, I also contributed to the design. The end result was that the cassette player sounded quite good, a million times better than the original sound and we didn't fundamentally change anything apart from a better design and a much more powerful bias/erase oscillator. The final design could have been put into production at the same cost as the original, and for a few pennies more the sound could have been further improved by changing to a better loudspeaker.

Back to the HiFi thing. There is a misnomer that a wide frequency response is a prerequisite and that reproduction of the extreme low and high frequencies is the holy grail. Yes, this is a very important aspect but it is not the fundamental criteria. Instead it is that, whatever the frequency band, the audio signal should be reproduced without distortion and artifacts. This is the part that is the most difficult because the ear is extremely sensitive to some types of distortion, while being almost oblivious to other kinds of distortion. It is just unfortunate that the ear is hyper sensitive to the distortion produced by transistor amps, especially class AB. The other aspect is what can be called smearing where definition is lost. The best illustration is perhaps base. At one extreme there is the impressive earth-moving rumble, so loved by the reggae boys and at the other extreme the articulate, flowing base with incredible slam that you get from some high end systems. By the way, I like both, but for a home system the latter is the only choice.

I made the seemingly extraordinary speculation that I thought you would benefit from listening to a HiFi system and I would like to clarify what i meant. It had nothing to do with the efficacy of a HiFi system as such. Instead it is my theory that by exercising your organs and brain you improve your performance, often radically. It is no different to the principal that reading a lot improves a persons spelling, comprehension, and writing skills. Having a system that produced the extreme frequencies, both high and low, would exercise you audio system the most and because the sound would be more detailed and clear, it would encourage you to listen more.

I had two experiences of this exercise principle. The first was when I was blinded in my right eye: by wearing a patch over the good left eye for about an hour every day I managed to gradually recover the site in the bad eye to a degree. In 2010 my left hand got badly burnt and the doctors said that I would probably lose the control of the thumb and index finger. This worried me greatly as it would have inhibited many activities so, in spite of the pain, I exercised my left thumb and finger as much as I could. The doctors were amazed how well the burn healed and how articulate the thumb and finger were. Now, apart from pink skin and problems with cold, the left hand is back to normal. I am saying this not to brag- in both cases my drive was purely self interest- but to illustrate the point that you can often achieve an awful lot by perseverance.

About not liking music: I suggest that it is just a matter of finding the type of music that you do like. For my part, I hated music, until rock arrived in the UK from the States in the late 1950s. Now, I probably like one percent of music, but the one percent is made up from a wide field from country to classical. I also find listening to audio books on a decent reproducing system is a lot less fatiguing than on most common equipment, especially low end ear buds.

You say you wish you could draw. Well the clue is in the word wish. Nobody will do anything by wishing. It is by study, persistence, and practice that you achieve skills that are not naturally given. If you doubt this just look at a pro in any field- they, with a few exceptions, practice constantly to achieve what appears to be a natural and effortless performance.

I would guarantee that, with the right training and practice, you would be able to draw quite well. If you ever think that your hand eye ordination, or any other innate brain processing, is not up to the job, think again. Just imagine the processing that goes on automatically to ensure that you stay upright and do not fall over, or the fantastic processing that allows you to load into your brain a complete image of a human face in an instant.

Talking about drawing, there was a fantastic girl, in more ways than one, who worked in the Technical Publications department. She could draw someones face in about 10 minutes and it was uncannily realistic and captured the expression exactly. When we were were doing a proposal, we would describe the intended system to her and she would draw more or less what we described, except better. Her artwork looked almost like the real thing and this was surprising as she had no technical knowledge whatsoever.

About playing the guitar- you may turn out to be a good guitarist. You never know until you try! I like the idea of playing by relays; perhaps that would help with my guitar playing. Don't forget to do a post if you come up with a scheme.

spec

 

[spec]

I played the trombone in the 7th grade (Just for 1 yr did not like band class), and I was too short to play the last note or 7th position, I think it was the C note. Also had trouble using the spit valve

Hi Mike,

So you are another engineering type with artistic (music) skills. I wish to hell that the music tuition at our school was better. I feel sure that if I had learned about music and how to play an instrument it would have helped me an awful lot. Mind you, I was not a very attentive pupil and was always thinking of something else, unless the lessons were maths, science, or metalwork.

spec

 

[Nikolai Petrenko]

Now I am trying to draw detail engineering drawings about my amp case, I have learn a little about basics of draw those type at school on previous year, too lucky!

 

[Nikolai Petrenko]

I love physics very much but I also like woodwork, metalwork, simple sculpture, bending hot glass and particularly electricwork, if can I will learn about gardenwork on the next summer holiday.

 

[spec]

Now I am trying to draw detail engineering drawings about my amp case, I have learn a little about basics of draw those type at school on previous year, too lucky!

What package are you using to do your drawing with?

 

[spec]

I love physics very much but I also like woodwork, metalwork, simple sculpture, bending hot glass and particularly electricwork, if can I will learn about gardenwork on the next summer holiday.

All good subjects, but you should add some general subjects too: language, literature and very important, dancing. Dancing is one of the most important of the social skills. Golf would be another good skill, but when you on the green let your boss win

 

[audioguru]

Very interesting AG, and well put.
It took me a bit of time to decode the last part of what you said. My feeling is that you are not one person but probably three, going by your posts on ETO that is. The two people that I like are the clever and knowledgeable designer and the teller of stories of experiences, as in the above post. I hope you don't mind me saying this.

Thanks, Spec, but do I dare ask about the third "me" that you do not like?

I liked classical music until I heard all of it too many times. The "live" symphony orchestra sounded awful because in the concert hall they used vocal mics with a peak in the upper mid-range for "presence" and used horn-sounding horn tweeters (Honk, Honk). The bass sounded boomy. My vinyl records sounded much better on my stereo.
I bought a Blaupunkt (German) car radio with cassette in 1975. The cassette also recorded but it used a distorting diode as its voltage controlled attenuator for AGC that I quickly removed. Its high frequency recordings dropped off at about 4kHz. When I was recovering for a couple of days from vasectomy operations I souped it up so its recording and playback frequency response was ruler flat from 30Hz to 15kHz. It recorded many pop songs from its FM radio when I was at work.

 

[spec]

Hi ag,

I was into country, blues, folk, skiffle and, of course, rock, but the first live performance that blew me away because of the clarity breadth and authority was an RAF band playing light music in a hall with very good acoustics. Although I hated the tunes and would not have listened to them for a moment from the radio, I was absorbed by the sound and enjoyed the whole concert as a result. Since then I have been to a few classical performances and quite a few rock etc concerts. The last was by Albert Lee, one of the best guitarists in the world. In every case the live music was way ahead of any reproduced music, the best sounding to me, being through Stax phones and amp.

spec

 

[Nikolai Petrenko]

What package are you using to do your drawing with?

No softwave, just paper, pencil and rulers.

 

[Nikolai Petrenko]

All good subjects, but you should add some general subjects too: language, literature and very important, dancing. Dancing is one of the most important of the social skills. Golf would be another good skill, but when you on the green let your boss win

Yes, I am learning language and literature pretty well. Dancing? Oh, my bad don't know it. Golf? Only can play when I become rich. I am very bad at sports, I only can swim well and a little martial art.

 

[Nikolai Petrenko]

About input coupling capacitors: I found WIMA polypropylene cap are available, 1uF but pretty expensive. I can accept this price if it can provide high-fidelity sound. The cheaper are nichicon 10uF KW for audio.

And 10000uF filter cap are Panasonic 6N29 for audio. Well?

 

[Nigel Goodwin]

About input coupling capacitors: I found WIMA polypropylene cap are available, 1uF but pretty expensive. I can accept this price if it can provide high-fidelity sound. The cheaper are nichicon 10uF KW for audio.
And 10000uF filter cap are Panasonic 6N29 for audio. Well?

You need to consider what professional audio equipment uses - and it's NOT silly priced capacitors that make imaginary claims about how they 'sound'.

 

[audioguru]

I have always used Epcos inexpensive film poly "whatever-they-use" for hi-fi audio designs and they sound perfect. You might be able to measure a slightly lower distortion by using expensive much larger polyprop capacitors but you cannot hear any difference.
Audiophools like to "hear" that a capacitor has a measurably lower distortion of 0.000008% instead of 0.000009% which nobody can hear.

 

[Nikolai Petrenko]

I don't understand. Can you explain again?

 

[audioguru]

I don't understand. Can you explain again?

The Wima polyprop capacitors you showed are high voltage and are huge. They are probably old and were used in vacuum tubes circuits.
The Epcos capacitors I showed are low voltage polystyrene or something that are inexpensive and are fairly small.
Both capacitors produce very low distortion that you cannot hear. The polyprop capacitor produces a little less distortion than the Epcos.

 

[large_ghostman]

What are the blue plastic type normally made of? I have a number of them and I am not sure which type they are. Shame your not nearer Nikolai, while Audio isnt my thing it would be cool to live near someone my age to do stuff like this.

I have some transistors etc to sort out, if I have any you can use and you want to pay the postage I can post them for you, I will check caps etc as alot of the spares I have I wont ever use

 

[audioguru]

The blue Epcos capacitors use a plastic film of a type of polyester (some people call it Mylar) with the metal deposited on it. Go online to see Epcos describe the big long name of the plastic.
I used Philips film capacitors many years ago when I worked for Philips. I also used Siemens very similar capacitors. Matsushita joined Siemens in 1989 to make the Epcos company with manufacturing in Germany. In 2006 Siemens and Matsushita sold Epcos to TDK (they used to make cassette tape in Japan).